The present invention is directed to braking devices for bicycles and, more particularly, to a braking device which is constructed so that the operating force of the brake lever can be varied as the brake lever is pulled.
A conventional bicycle brake is shown in FIG. 8 and disclosed in JP 5-16865. As shown in FIG. 8, a brake lever 3 is mounted via a pivot shaft 4 in a manner which allows said brake lever to pivot on a lever bracket 2 which is fastened to a handle-bar 1. Furthermore, a coil spring 21, one end of which is free, is attached to the aforementioned lever bracket 2 via a bolt 20, so that when the brake lever 3 is pulled, an extension part 3b extending from said brake lever 3 contacts the free end of the aforementioned coil spring 21 after the brake lever 3 has pivoted through a fixed stroke.
In this conventional braking device, as is shown in FIG. 9, the resistance to operation of the brake lever 3 increases when the brake lever 3 is pulled through the fixed stroke so that the extension part 3b contacts the coil spring 21. As a result, a larger operating force is required for any subsequent operation of the brake lever 3, so that the cyclist is able to sense the operating stroke of the brake lever 3.
In the above mentioned conventional braking device, as is shown in FIG. 9, the slope of the operating force of the brake lever 3 vs. the braking force only slightly changes in the vicinity of the operating point (B) where the extension part 3b of the brake lever 3 contacts the coil spring 21. Under normal operating conditions, the increased force can be sensed, and the cyclist may control the operation of the brake lever accordingly. However, in high performance situations such as racing the cyclist may not have sufficient time to give lengthy consideration to the braking characteristics. As a result, the cyclist may not apply the desired amount of braking force, thus resulting in decreased performance.